Abstract

High resolution scanning tunneling microscopy has been applied to investigate adsorption and self-assembly of large organic molecules on the TiO2(011) surface. The (011) face of the rutile titania has been rarely examined in this context. With respect to possible industrial applications of rutile, quite often in a powder form, knowledge on behavior of organic molecules on that face is required. In the presented study we fill in the gap and report on experiments focused on the self-assembly of organic nanostructures on the TiO2(011) surface. We use three different kinds of organic molecules of potential interest in various applications, namely, PTCDA and CuPc representing flat, planar stacking species, and Violet Landers specially designed for new applications in molecular electronics. In order to reach a complete picture of molecular behavior, extended studies with different surface coverage ranging from single molecule up to 2 monolayer (ML) thick films are performed. Our results show that the adsorption behavior is significantly different from previously observed for widely used metallic templates. Creation of highly ordered molecular lines, quasi-ordered wetting layers, controlled geometrical reorientation upon thermal treatment, existence of specific adsorption geometries, and prospects for tip-induced molecule ordering and manipulation provide better understanding and add new phenomena to the knowledge on the (011) face of rutile titania.

Received 17 January 2011Accepted 03 May 2011Published online 08 June 2011

Acknowledgments:

This work was supported by the 7th Framework Programme of the European Commission within the Coordination Action “Nano-scale ICT Devices and Systems, NanoICT,” Contract No. 216165, and by the Polish Ministry of Science and Higher Education under Contract Nos. 0313/B/H03/2009/36 and 1802/B/H03/2010/38. S.G. would like to acknowledge support received from the Foundation for Polish Science within START program (2010 and 2011). A.T. acknowledges generous support from the Natural Sciences and Engineering Research Council of Canada as a Vanier Canada Graduate Scholar.